Yes, both the USB and SD card (via adapter) are accessible when plugged into the carrier board and it's booted from the eMMC. I can see the /boot and /rootfs folders in both.
The Oak-D board has 2 USB ports, I have tried using both.
Steps performed to enable booting from USB:
- Install RPiOS on USB/SD card using RPi Imager
- Power on the board, booting from eMMC
- Navigated to the recovery usbboot/recovery and updated the boot.conf BOOT_ORDER to 145
- Run the ./update-pieeprom.sh script
- Transferred over the recovery folder from the Oak-D-CM4 to a Windows 7 machine
- Turned off the Oak-D-CM4, removed peripherals and power, then set the on-board jumper that is equivalent to the J2 jumper before reconnected the power and connecting the Windows host to the Oak-D board via microUSB
- Installed rpiboot on the Windows machine
- Tested the connection by running the rpiboot.exe (successfully connected), before terminating the process and reconnecting
- Run '"<RPIBOOT_PATH>/rpiboot.exe" -d <PATH>/recovery' - seems to succeed
- Unplug the microUSB, reset the jumper and removed the power from the Oak-D, insert OS USB and power on
At this point, it seems to attempt to boot from USB, but fails with the err-19 message from before, and I have to power cycle to try booting again. With the USB removed, then it successfully boots from the eMMC after a power cycle.